Semiconductor manufacturing required strict environmental control, especially dust, airborne microbes, aerosol particle and trace moisture, generated by equipment and people during the process. Cleanrooms are adopted by manufacturer to improve yield and increase throughput. A cleanroom is designed to maintains a very low concentration of airborne particulates according to ISO 21501-4. ISO 14644-1:2015 specifies the classification of air cleanliness in terms of concentration of airborne particles in cleanrooms and clean controlled environments as Figure 1.

Semiconductor manufacturing required strict environmental control, especially dust, airborne microbes, aerosol particle and trace moisture, generated by equipment and people during the process. Cleanrooms are adopted by manufacturer to improve yield and increase throughput. A cleanroom is designed to maintains a very low concentration of airborne particulates according to ISO 21501-4. ISO 14644-1:2015 specifies the classification of air cleanliness in terms of concentration of airborne particles in cleanrooms and clean controlled environments as Figure 1.

Figure 1: ISO 21501-4 clean room standards (https://www.cleanroomtechnology.com)

Particle counters are essential part of cleanroom, used to count the number of particles in clean room and measure their size. It indirectly monitoring, classifying, and diagnosing the source and complexion of contaminants in cleanroom operations. Manufacturers of semiconductors, flat panel displays, and hard disk storage units have long recognized the relationship between improved air quality and the increase of final yields.

One of the common particle counters used in cleanroom is the Light Scattering Airborne Particle Counters (LSAPC). LSAPC consist of light source (laser), sample air suction system, lens, and sensor as Figure 2. Optical particle counters don’t directly indicate the size of a particle directly. Instead, they measure the diameter of the light scattered and suspended in air. Particle size, also called particle diameter, is measured after a photon detector converts the size and frequency of scattered light into electrical signals

Figure 2: Schematic diagram for Light Diffraction/Scattering Airborne particle counter: (a) parallel beam arrangement, (b) converging beam arrangement.

Regular particle counter calibration is an essential part of cleanroom maintenance, so they can stay functioning at their peak productivity. Cleanrooms certifications require certified particle counters with regular maintenance and calibration for the ongoing accuracy of the particle counter. To Calibrate airborne optical particle counters in electronic manufacturing, especially cleanroom, a size standard with a mean size standard uncertainty of ≤2.5% are required. Thermo Scientific 4D series size standard can calibrate airborne optical particle counters in compliance with ISO 21501-4. It is ideal for calibrate ISO 21501-4 classified particle counter in ISO 14644 classified cleanroom. The specification of All the 4D series size standards comes with Certificate of Calibration and Traceability to NIST with specification as shown in Figure 3.

Figure 3: Specification of 4D series (Dry) size standard, used to calibrate airborne optical particle counters in pharmaceutical and electronic manufacturing labs and cleanrooms

Additional Resources:

  1. https://blog.gotopac.com/2017/08/18/what-is-a-particle-counter-how-do-particle-counters-work-what-are-they-used-for/
  2. https://www.sciencedirect.com/science/article/pii/S0143816601000902
  3. https://www.cleanroomtechnology.com/news/article_page/What_is_ISO_8_cleanroom_classification/180543
  4. https://www.golighthouse.com/en/blog/what-is-particle-counter-calibration-and-why-is-it-important-456
  5. https://www.thermofisher.com/order/catalog/product/4D-10?SID=srch-srp-4D-10




 

 

Contact Us

Would you like to sign up for the newsletter from Thermo Fisher Scientific (including its affiliates) and receive regular updates on the latest applications, events and product information?
*By submitting this form, you agree to be contacted by a Thermo Fisher Scientific Specialist/Sales Representative.
Thermo Fisher Scientific (including its affiliates) processes your information as set out in the Privacy Information Centre which includes information about your rights. We may use your Personal Information to contact you about our products/services, events or other information we feel may be of interest to you.
You may unsubscribe to our newsletter by clicking the unsubscribe link in the emails received